st forth
again.

"All we need to make it complete," he said, "is D'Artagnan. I wonder
if we'll find him."

Jack made no answer. His thoughts were busy turning over plans for the
rescue of his father. Bob, too, was unusually silent, thinking of the
parting from his own father and the latter's anxiety which almost had
prevented his making this venture. Frank pursed his lips to whistle,
thought better of it, and jogged along as silent as his companions.

So they rode hour after hour, only the creak of leather, the
occasional stumble of a horse or the distant call of a coyote breaking
the stillness. At length a low range of foothills, upflung before
them, began to take shape out of the darkness with their near
approach. Presently Jack called a halt.

"Somewhere in there," said he, "lies Tom's cave."

It was in the early hours before dawn, when the darkness if anything
becomes more intense. A chill nipping wind long since had caused the
boys to unroll the rubber ponchos strapped to the back of their
saddles, and drape them over their shoulders. As they stood now in the
eerie darkness, striving vainly to locate the landmarks of tree and
rock which Tom had given them, the howl of a hunting coyote floated
down the wind. The sensitive Frank shivered.

"That sends the gooseflesh up my spine," he said.

"Are you scared?" asked Bob.

"I'm scared stiff," averred Frank. "My hair is standing up so straight
I wonder how my sombrero stays on."

"Me, too," said Bob.

"Liar," said Frank.

"You're another," said Bob. "You're not scared. I know you too well."

They grinned affectionately at each other. Jack who meantime had been
investigating, turned with a worried expression.

"I've followed Tom's directions faithfully," he said. "He said to lay
our course south by south-west and showed me what he meant on my
compass. I haven't deviated a hair's breadth. Somewhere about here
should be the first landmark--three rocks shaped like a camel lying
down. But I can't see them."

"Nothing to worry about in that," said Frank. "Probably we haven't
gone far enough. Let's push on."

"That must be it," said Jack with relief. "Well, come on."

Before they could get into motion, however, Bob uttered a warning
whisper.

"Listen," he said. "I heard a horse stumble behind us on the trail."

They listened breathlessly a moment, but no further sound was heard.

"Keep your guns handy," whispered Jack. Whenever the three were
together h